Composition for cleaning printing-surfaces.



F1 NrrEp- STATES Patented July 18, 1905.

FREDERICK FORSTER, OF NEW YORK, N. Y.

COMPOSITION FOR CLEANING PRINTING-SURFACES- SPECIFICATION forming partof Letters Patent No. 795,215, dated July 18, 1905.

Application filed November 25, 1904. Serial No. 234,307.

To all] 1071/0721 it mar/y err/warn:

Be it known that I, FREDERICK FORSTER, of 838 Eagle avenue, in the cityand county of New York and State of New York, have invented certain newand useful Improvements in Cleansing and Preparing Plates Used forLithographic-Printing Purposes; and I hereby declare that the followingis a full, clear, and exact description thereof.

This invention is an improved composition for cleaningprinting-surfaces, particularly lithographic plates, such as aluminium,zinc, German or American printing metal, and other materials used formaking printingsurt'aces for plate-printing. The composition is alsouseful for cleansing other surfaces and objects, and therefore I do notwish to restrict myself specifically to its use with any particularmaterial or printing-surface.

The invention consists in the novel composition for cleaningprinting-surfaces, as hereinafter described and claimed.

1 preferably use two cleaning solutions, which I shall call solution No.1 and solution No. 2. These solutions are compounded as follows:

Solution A 0. 1.--Bichromate of potassium, one part; sulfuric acid, twoparts; water, twenty parts.

Solution N0. 3.-Powdered purified alum, four parts; carbonatrwf soda,four parts; carbonate of potassium, one part; ten-per-cent. solutiongallic acid, ten drops; caustic hydrate of soda, four parts; water,thirty-two parts.

In compounding solution No, 2 I prefer to first mix the alum and water,care being taken to remove or keep out any foreign substances orchemicals. The other-ingredients are then added thereto.

1 do not herein claim solution No. 1, nor do I restrictmyself totheparticular solution N0. 1 set forth, the present invention residing inthe principal solution, No. 2; but I [ind best results are obtained byusing the two solutions successively, as hereinafter described, whencleansing printing-surfaces.

In practice the solutions are used successively or alternately toproduce the best results. However, the solutions in some instances maybeseparatelyused with beneficial etfects, and therefore I do not wish torestrict myself to the use of both at all times.

For cleaning aluminium, zinc, white metal, German printing metal,American printing metal, and all other materials commonly used forlithographic-printing purposes in the form of plates I proceed asfollows:

First, place the plate in an ordinary asphaltuin-lined trough and applysolution No. 1 by pouring same evenly thereover. Let solution remain onplate for about five minutes. Then rub plate with felt or other softmaterial for the purpose of removing surplus dirt. Then flush plate withwater. Dry plate.

Second, then apply solution No. 2 in the same manner as above bydistributing evenly over plate and rubbing gently at intervals for sixor seven minutes with felt or other soft material, which will remove allink, grease, or other foreign matter. Flush the plate again with waterand then again apply solution No. l for a minute or two. Then give platea final washing with plain water and put in rack to dry. The plate isnow thoroughly cleaned and prepared for use for lithographic printingWithout any other preparation or solution being used and without anyrubbing except as stated above.

As the strength of the chemicals varies somewhat, the hydrometer testfor solution No. 2 is 80. The hydrometer referred to is that known onthe market as the actinometer. The solution of gallic acid is to be usedin the proportion stated when each part represents an ounce-that is, tendrops of gallic acid to each thirteen ounces of chemicals used,exclusive of water.

The solution No. 2 will not only clean prepared plates, but is useful toprepare new plates for printing, as it will remove the grease or foreignsubstances that are in or on the metal of such plates and must beremoved before perfect printing is'possible, and the use of the solutionon either new or old plates is included herein. The'solution No.

white metal, and

of ten-per-cent. solution gallie acid; four parts caustic hydrate ofsoda and thirty-two parts Water, substantially as described.

In testimony that I claim the foregoing as my own I al'lix my signaturein presence of two Witnesses.

FREDERICK FORSJT'ER. in presence of" Hunnura W. CLARK, Guoneu Rmrz.

